This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Lambda-repressor has been identified experimentally as one of the fastest folding proteins with an observed relaxation time, in case of one mutant, of 10 microseconds. Accordingly, we propose to perform protein folding simulations of multi-microsecond duration in order to characterize the folding free energy landscape and propose even faster folding mutants that approach a proposed speed limit of 1 microsecond or fold even faster. The projects will make it possible to directly compare experiment and simulation.